"I'm a sole proprietorship with no employees. What is the maximum allowable contribution to my solo 401k?

[trinasessler]

I've made the annual contribution limit of $18,500. Turbo tax is telling me I can contribute another $9155. I'm assuming that is the employer contribution based on 20% of my Schedule C net Earnings.  Is that correct?"

[DDollar · Accepted solution]

In addition to the $18,500 contribution, you can contribute up to 20% of your net self-employment income as an employer (your business income minus half your self-employment tax). The maximum amount a self-employed individual can contribute to a solo 401(k) for 2018 is $55,000 if he or she is younger than age 50. Individuals 50 and older can add an extra $6,000 per year in "catch-up" contributions, bringing the total to $61,000.

[trinasessler]

Do I have to pay myself a salary or is the net profit on Schedule C in essence considered my salary?  

[DDollar]

You do not pay yourself a salary when you're self employed.   You are doing things correctly.